Post-processing of Commercial CMOS Chips for the Fabrication of DNA Bio-FET Sensor Arrays

A BioFET array can be fabricated by post-processing of a standard CMOS chip if temperatures are kept below 450 °C and radiation or ion-bombardment damage is minimized. The processing starts with encapsulation by deposition of a low stress, electrolyte-impermeable silicon nitride layer by PECVD at 375 °C. Anisotropic reactive ion etching with an inductively coupled plasma using C4F8 and Ar was used to remove the silicon nitride and oxide layers …